Automatic thread-chasing tool



F. J. HEYBACH AUTOMATIC THREAD CHASING TOOL Sept. 21 1 926.

2 Sheets-Sheet 1 Original Filed Oct. 23, 1922 Sept. 21 1926.

F. J. HEYBACH AUTOMATIC THREAD CHASING TOOL Original Filed Oct, 25. 1922 2 Sheets-Sheet 2 31M; freak/787k! I Patented Sept. 21, 1926.

\ use (FREDERICK J. I-IEYBAGH, or SAVANNAH, enoaern.

AUTOMATIC THREAD-CHASING TOOL.

v Application filed October as, 1922, Serial in. 596,330. Renewed August a, 1926,

sive cuts, said tool being provided with means for retracting the, cutter from the work and pro ecting it thereagainst between each cut, said means actuating auto matic feeding means for advancing the cut-' ting edge in a depth direction a predeter mined distance at each cut.

Still another object of the invention is the provision of means for predetermining the depth of each cut and also the depth of the finished thread. i

A further object of the invention is, the construction of a thread chasing toohwhich is presented angularly to the work and automatically fed thereto, at the angle of its presentation so that the leading edge only of the cutter performs the cutting operation, thus avoiding chattering or gouging of the work, this being a common fault of thread cutting tools, which as ordinarily constructed cut both sides of the thread at once. with the above and other objects in View, my invention consists in the improved automatic. thread chasing tool illustrated in the accompanying drawings, described in the "following specification, and particularly claimed, and in such variations and modifications thereof as willbe obvious to those skilled in the art to which my invention relates.

in the erawings accompanying and forming a part of this specification, and wherein the preferred embodiment of my invention is illustrated: j lligure 1 is a plan View 01 my improved automatic thread chasing tool. Figure 2 is a side elevation on a slightly larger scale of the tool shown in Figured, parts being broken away.

Figure 3 is an elevation showing a detail of the invention'with the parts in the posi-' tion assumed when the tool is retracted from the work;

Figure 4 is a side elevation of the tool shown in Figure on a slightly larger scale taken from the side opposite that shown in. Figure 2. Y 7 1 I Figure 5 is a cross section taken-along the line 55 of Figure l. V

Ptererring now in detail to the several figures, the numeral 1 represents the casing of the tool which is formed with a polygonal bore 2 adapted to function as a guide way for'tlie slidable cutter block The bracket 4- which 'ishereshown as integral with thefcasi'ng, l, but rmay' be attached" thereto in any suitable manner carrieslat its rearward endfla platen provided with the upstanding lugs 6 and forming a'fslide for the cross head 7. L

Said cross head 7 18 formed with a bore 8 I leading from its forward face 9 to a recess 10. A coupling member 11 is provided having a reduced portion 12 passing through the bore 8 and journally secured to the cross head 7 b rmeanso'f the nuts 18 housed inthe recess 10. The forward end of the member 11' is threaded and "passes into a ,threaded socket 1a in the ZtCiJflCGIIi'J end ofthe cutter block. A ratchet cylinder15 is keyed'to an intermediate portion of thefmember 11. This ratchet member may be turned either manually or mechanically and is provided on "one'side with knurled surface and on the outer face with a plurality of-peripherally arranged" ratchet teeth 16. Itis apparent that j by: rotating the ratchet cylinder relatl ely to the casing 1 the threaded member is advanced or retracted withrelation to the socket 1% thus varying the' dist'an'ce oi the cuttter block from the ratchet cylinder. A graduated' scale is'provided ,adjacent theratchet teeth, each mark represent ing adefinite degree 0t depth-cut, for instance the thousandth part of an inch and Y is used to determine the depth 'ofa thread without the use of calipers or micrometers;

The cross head 'Z and cutter block 3*are joined together'by means of the'threaded member 11 and means-are provided for iinparting a reciprocatory movement to the cross headj'whereby the cutter block 3 and the cutter '17 are finoved eitl'ier towardor' away from the work. 'Tliecmeanshere' em;

ployed for accon iplishing this freciprocatory' movement consist 'of shaft; 18 j'ournally" carried by the lugs 6 and'having aha'ndle 19 jsecured thereto by the set'scre'W20. "A

yoke 21 is arranged between the lugs.i 6,'

which has a bore aligning with the aper I tures in the lugs 6 and through which the cross head 7 by means of the link 47.

shaft'lS passes. Said vyoke is secured to said shaft by means of the set screw 22.

The thumb screw 23 penetrates one of the lugs 6 and engages a notch 2-1 in the shaft 18 holding the latter rigid, or tight when it is, desired to dispense with the function of the reciprocating mechanism holding the r 0f the casing l by means of a thumb screw .28, the latter passing through a slot in said gauge plate and being serured to the wall ,of the casing. The gauge plate 27 and the head, of the cap screw'26 cooperate to determine and limit the depth of the thread to be out. A gauge, not shown, equal to the depth of the desired thread is placed between the cap screw and the gauge plate and'the latter pushed against said gauge and secured from further movement by turning the thumb screw '28. The gauge is then withdrawn and'the space between the "head of the cap screw and the gauge plate represents the extreme distance through Which the cutter block may be advanced in cutting the thread. In order to protect the gauge plate and cap screw from forcibly striking each other during the operation of the tool in such a manner that the depth adjustment might be altered, a set screw 29 is secured to the bracket 4, passing through a threaded aperture in said bracket and through a slot30in theend of the cross head. .Theinner end of said set screw projects into thepath of movement of the yoke 21 and may be adjusted to contact with said yoke exactly at the moment when the cap screw 26 andthe gauge plate 27 come together.

Means are provided for automatically feeding the cutter 17 forwardly in a depth direction 'which in the present illustration takes the form of a pawl 31 pivotally mounted'upon the casing 1 by meansof the cap screw '32 and having one end 33 thereof arranged to contact with ratchet teeth 3st and thereby to actuate theratchet cylinder 15 and the threaded member 11 thereto secured. The pawl 31 is provided with tensloning'. means, consisting of a spring 36',

L one end of which hooks in theslug 35, the

other end being fastened to a stationary post37, said spring being normally tensioned "to inai'ntain the end 33 of the pawl biased in the direction of the ratchet cylinder. Stop means 38 is secured to the casing 1 adjacent the opposite end 39 of the pawl and an adjusting screw-v 40 passes through said end carrying the usual lock nut ll. The adjusting screw 40 normally contacts with the stop 38 to determine the position of the end 33 of the pawl when the latter is out of contact with the ratchet teeth 3-1.

lVhen the handle 19 is turned in a direction to retract the cross head '7 and cutter block 3, the ratchet cylinder 15 moves away from the pawl 31, as, shown in Figure 3, permitting the end 33of the latter to assume its extreme positionby movement in a counter-clockwise direction as viewed from Figure l-Vhen the handle is turned in the opposite direction and the parts are advanced toward the work, the, ratchet cylinder 15 first engages the end 33 of said pawl. Further inward movement of sail ratchet cylinder forces the end of said pawl to move arcuately to the left as viewed from figure 3 causing a partial rotation of the ratchet cylinder and consequent relative movement between the threaded member 11 and the cutter block projecting the latter slightly forward in a depth direction. This movement is completed by the "time the cutter 17 engages with the work and the pitch of the threads on the threaded member 11 is such as to make the automatic feeding movementirreversible so that the cutter 17 is locked against recession from its depth position. v

, By adjusting the screw 10 the arc of move ment of the end 33 of the pawl 31 ischanged so that jitv may be determined whether said pawl shallrotate the ratchet cylinder the distance of one, or more than one tooth at a single movement of the handle 19.

The casing 1 is carried by a shank .2 of

polygonal shape and adapted to be clamped in the too-l post 4:3. The shank extends angularly from said casing'so that the tool is presented at an angle to the axis of rotation of the work as is indicated in 'Figure 1. The cutter 17 is so shaped that oneside thereof lies parallel to a sideof the thread the leading edge only of said cutter performing the cutting operation as is clearly shown at 44in Figure 1. By 'thisarrangement it is possible to cut the thread smoothly with a thin shaving without chattering of the tool or gouging the work. The cutter is removably secured in'an oblique channel 45 as shown in Figure 2' and held rigidly in position by means of the set screw 46;

In the operation'of my improved automatic thread chasing tool, it is set up in the tool post angularly as shown in Figure 1. The cutter 17 is then projected against the work by manually turning the ratchet cylinder 15, the bar of course, at the time, be unthread'ed. A gauge representing the cle 'ath of the desired thread is then introure 1.

ducted between the cap screw'26 and the gauge plate- 27 and the latter secured in a position touching said gauge. The gauge is then removed. The thread isto be formed by a succession of cuts, the tool travelling axially relatively to the bar-stock. If the material is such that a light out is essential the operator adjusts the screw so that the arc traversed by the end 33 of the pawl 31. is sufficient to move the ratchet cylinder a distance equal to the space of one of the teeth 34;. Should the nature of the material permit aheavy cut the adjusting screw 40 is retracted accordingly to permit the pawl 31 to rotate the ratchet cylinder 15 an angular distance sufficient to give the desired cut.

lhe handle 19 is thenv turned in a direction to advance the cutterwlnle the tool travelsaxially in the direction of the arrow in Fig- The handle 19 is then reversed Wltlidrawing thecutter l7, and the tool returned to its original position relatively to the barstock. The handle 19 is then again moved in a forward direction the change in depth of the cutter being accomplished through the actuation of the ratchet cylinder 15 by the pawl 31 before the cutter 17 engages the stock. The tool again travels in the direc-' tion of the arrow. This operation is repeated until the thread is completed, it being impossible to carry the thread to too great a depth on account of the limit to the depth movement of the tool imposed by the contact of the head of the cap screw 26 with the gauge plate 27.

While in the embodiment above described I have exemplified my invention by the use of specific mechanical elements it is to be understood that I do not consider the invention limited to the utilization .of said specific mechanisms, but that it extends to any and all mechanical arrangements which may be included within the terms of the claims. Having described my. invention what claim as new and desire to secure by Letters Patent, is

1. A thread chasing tool comprising a casing, a cutter block slidably mounted in said casing, a cross-head a coupling member swivelly mounted in said cross-head and A thread chasing tool adapted to co-' operate with a rotating work holder comprising a casing, a cutter block slidably I mounted in said casing, means for reciprocating said cutter block, a threaded couphng member connect-mg said reciprocatfor advancing said cutter block along the member.

mg means and said cutter block and means threads of said coupling member at each reciprocation thereof for advancing the L l-t,

ter a predetermined distance toward said work holder. I g I 3. A thread chasingtool adapted to coop erate with a rotating work holder comprising a casing, a cutterv block slidably mounted in said casing, means for reciprocating said cutter block, a threaded coupling member connect-in said cutter block and reciprocating means, means for rotating said coupling member to advance the cutter block along the threads thereof, and means for actuating said rotating means upon each reciprocation of said reciprocating means. I

i. A thread chasing tool adapted to cooperate with a rotating work holder compris ing a casing, a cutter block slidably mounted in. said casing, means for reciprocating said cutter block, a threaded coupling member connecting said reciprocating means and cutting block and a pawl and ratchet movement actuatable upon reciprocation of said reciprocating means to rotate said couplingmemher for advancing thecutter block along the threads thereof a predetermined distance in a depth direction.

5. A thread chasing tool adapted to coop erate with a rotating work holder comprise ing a casing, a cutter block slidably. mounted in said casing, means for reciprocating said cutter block in a direction angularly with respect to a plane perpendicular to the axis of rotation ofsaid Work holder, a threaded coupling member connecting said reciprocating means and cutter block, pawl and ratchet means for imparting astepby step rotation to said coupling member at each reciprocation of said reciprocating means, to advance the-cutter block along the threads of said coupling member. a predetermined distance in a depth direction and means for adjustably chan ing the length of the step of'rotation oi said coupling said casing, means for repeatedly reciprocat mg said cutter lOlOCl, I1i6&11S actuat-able upon each reciprocation of'said cutter block for advancing the latter a'predetennined dis tance in a depth direction away from said casing and means for setting a final limit to the aggregate distance said block may be advanced,

7. An automatic thread chasing tool com prising a casing, a cutter block slidably automatic thread chasing tool com{ prising a casing, a cutter block carried by for) mounted in said casing, means for repeat 5 edly reciprocating. said cutter block, a

threaded coupling member connecting said reciprocating means and cutter block, means actuatable upon each reciprocation of said reciprocating means for advancing the cutter block along the threads of said coupling member for moving said cutter block a preprising a casing,

reciprocation of said reciprocating means for imparting a step by step rotation to said couphng member for advancing SitlCl' coupling block along the threads of said couplingmember a predetermined distance in a depth direction away from said casing.

'9. An automatic thread chasing tool comd a cutter block slidably mounted in said casing, means for reciprocating. said cutter block, a threaded coupling member connecting said reciprocating means and cutter block, means actuatable upon each reciprocation of said reciprocating means to impart a step by step rotation to SEE-1d coupllng member for advancing said cutter block along the threads of said coupling member a predetermined distancein a depth direction away from said casing and means for adjustablychanging, the length of each step of rotation of said coupling member. I I a 10. An automatic thread chasing toolcomprising a casing, a cutter block slidably mounted in said casing, a stop on said cutter block projecting through a slot in said casing, and an adjustable gauge plate on said casing co-actable with said stop.

11. An automatic thread chasing tool comprising a casing, a cutter block slidably mounted in said casing, means for reciprocating said cutter block, means actuatable' upon reciprocation of said cutter block for advancing said cutter block a predetermined distance in a depth direct on, a stop on said cutter blockprojecting through a slot in said casing, and an adjustable gauge plate coactable With said stop to limit the total depth. movement of said cutter block.

In testimony whereof I aiiix my, signature.

FREDERICK J. HEYBACH. 

